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Test System: Phenom II X4 955 And Gigabyte MA790FXT-UD5F

DDR3 Memory Scaling On AMD's Phenom II X4
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Processor: AMD Phenom II X4 955


The Phenom II X4 955 is AMD’s latest addition to its state-of-the-art processor family. Running at 3.2 GHz, the 45 nm DSL SOI processor still isn’t capable of beating the Intel Core i7, but the 955 Black Edition flagship is typically even cheaper than Intel’s Core i7-920 entry-level offering, not to mention the cost advantages for AMD on the platform side. The Phenom II X4 955 matches and sometimes beats a Core 2 Quad Q9550, and hence offers a great price/performance ratio. 

The maximum thermal power is specified at 125 W, which is a bit below the i7's 130 W TDP envelope. In addition, system-wide power consumption is lower than on a Core i7 solution; this isn’t significant, but represents another small benefit for AMD. Even though it cannot beat Intel, AMD clearly is competitive again.

All Phenom II X4 processors are manufactured using AMD’s 45 nm process. They come with 6 MB of shared L3 cache and 512 KB L2 cache per core. All 45-nm AMD CPUs can be inserted either into an AM3 or an AM2+ socket, as the integrated memory controller supports both DDR3 and DDR2 memory (not at the same time, though). Not all Phenom II X4 CPUs support DDR3; only the models 955, 945, 805, 810 and 910 are DDR3 versions for socket AM3—all other models are for socket AM2+ only. We used the 955 top model, as differences in memory performance would be most visible on such a system. And we stayed with DDR3 memory, which is what you should get today.

Motherboard: Gigabyte MA790FXT-UD5F

After having chosen the fastet processor possible for this project, we looked for a motherboard to support our testing. Chris Angelini used two Asus motherboards: the M3A78-T for socket AM2+ (AMD 790GX) and the M4A79T Deluxe for Socket AM3 (AMD 790FX). Therefore, we used a Gigabyte MA790FXT-UD5F this time. The board uses the same 790FX chipset, which is still considered the best choice for Phenom II, and it implements Gigabyte’s latest Ultra Durable 3 technology. This basically means intensive use of copper to reduce electrical resistance and theoretically improve overclocking capabilities. Unfortunately, this wasn’t our focus today; we simply took advantage of this board’s flexible memory configuration options.

A heat pipe on the MA790FXT connects the northbridge, southbridge, and the voltage regulators, which have a total of 10 phases. Two of them will only be used at high loads, resulting in an effective 8-phase design for mainstream processors that don’t require a lot of power.

The board has two x16 PCI Express 2.0 slots and three additional x1 PCIe slots. Despite the 6 SATA/300 storage ports available through the SB750 southbridge, Gigabyte added two additional JMicron SATA controller, which adds four more ports. These can be used for the Smart Backup RAID feature, or as additional storage ports. Up to 12 USB 2.0 ports, 106 dB signal to noise ratio HD audio, dual Gigabit LAN, and legacy floppy/ATA ports are available as well.

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  • 6 Hide
    cangelini , June 4, 2009 6:50 AM
    judeh101DDR3 memory scaling on AMD's Phenom II X4, why don't cha do one for Intel as well? I'd love to see the performance on the Core i7 platform


    It's coming!
  • 0 Hide
    cangelini , June 4, 2009 7:45 AM
    Much thanks judeh, I appreciate your feedback!

    Best,
    Chris
  • 6 Hide
    Antman56 , June 4, 2009 7:59 AM
    The real trick to seeing a greater discrepancy between different clock speed memory(s) could be done by overclocking the CPU-NB. Using SiSoftware Sandra, I get 13.2 GB/s with DDR2 @ 1066 MHz (5-5-5-15) on a 3.4 GHz Phenom II 940 X4 with a 2.4 GHz CPU-NB.

    Overclocking that Integrated Memory Controller is key!

    ...Just a suggestion :p 
  • -2 Hide
    empstar , June 4, 2009 8:34 AM
    why always missing something..... where's the DDR2 RAM ?? should include in the chart!! very disappointed.
  • 0 Hide
    EQPlayer , June 4, 2009 8:47 AM
    Yarr, good point. Overclocking the CPU/NB on these chips seems to have nearly (well that might be a bit of an exaggeration) as much of an effect as overclocking the CPU itself.
  • -1 Hide
    DjEaZy , June 4, 2009 9:25 AM
    ... it is getting better and better with TOM's... more information to compare... for the last month it's enjoyable to read...
  • 0 Hide
    Anonymous , June 4, 2009 10:16 AM
    Why you didn't have tried a 'synchronized' configuration with base clock, north-bridge, memory and cpu core running on integer or semi-integer divisors ? like 266MHz base clock, 1068 MHz memory clock, 2136 MHz north bridge & HT clock and 3199 core clock.
    This configuration is possible even with DDR2, with lower latencies memories and is much closer to the DDR3/1333 configuration than you think.
  • 2 Hide
    cinergy , June 4, 2009 10:43 AM
    Very nice bench for AMD people.
  • -7 Hide
    apache_lives , June 4, 2009 10:59 AM
    judeh101DDR3 memory scaling on AMD's Phenom II X4, why don't cha do one for Intel as well? I'd love to see the performance on the Core i7 platform


    Why does everyone vote down a valid question?
  • -1 Hide
    apache_lives , June 4, 2009 11:04 AM
    and this is the same old picture - mainstream ram has always been the best price:p erformance, no point in chancing extreme memory, and "high end" memory is only good for overclocking etc
  • -1 Hide
    chripuck , June 4, 2009 11:47 AM
    apache_livesand this is the same old picture - mainstream ram has always been the best priceerformance, no point in chancing extreme memory, and "high end" memory is only good for overclocking etc


    I wouldn't call the two top performers mainstream... with those timings there at least a step above main stream. Now to your point they're definately not the top of the line, but anyone with a clue about electronics knows the best bang for your buck is never the cheapest and never the most expensive... the sweet spot is always in the middle.
  • -3 Hide
    Kill@dor , June 4, 2009 12:39 PM
    Can't wait for Intel's review as well.
  • 1 Hide
    coopchennick , June 4, 2009 12:43 PM
    Soo... I guess Toms just decided not to do the SBM giveaway?
  • -1 Hide
    Kill@dor , June 4, 2009 1:00 PM
    I have to kind of admit this was a little unfair because DDR3 2000 was not in this line up...why i'm not sure. Intel's processors can utilize DDR3 2000 very well with timings like 9-9-9. But even so, its important to show how DDR3 2000 can perform with AMD and the benefits it has for a stable high clock on your system. If you plan on overclocking 3.0GHz to about 3.6 or 3.8 DDR3 1333-1600 is key in my opintion. Anything higher than 4.0GHz will benefit stability with DDR3 2000. I hope Toms can get a review to show this...
  • -1 Hide
    buzznut , June 4, 2009 1:31 PM
    I was disappointed that the memories weren't tested more with overclocking. You did a little bit with the 800 speed, but who is gonna run their ram at that speed?

    Well, nice article. It makes me wonder why ddr3 memory is not more effective, does not offer much beyond ddr2. It seems to make a considerable difference in video cards, ddr2 vs ddr3. Will they skip ddr4 and go to ddr5 for mainboard memory, like the upper end ATI cards?

    As it has been for a few years, latency is the most important factor with AMD processors.
  • 0 Hide
    sublifer , June 4, 2009 1:57 PM
    Only testing in 2T command rate?
  • 2 Hide
    Anonymous , June 4, 2009 2:26 PM
    Quote "Why does everyone vote down a valid question?"

    Because if that person would have read the first page of the article, they would have seen that a Intel article is coming.......
  • 2 Hide
    HVDynamo , June 4, 2009 2:30 PM
    apache_livesWhy does everyone vote down a valid question?


    Because it says there is an intel article to follow at the bottom of the first page of the article. He posted before reading.
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